1. Field of the Invention
This invention relates to a microstrip array antenna, especially a broad-band dual-polarized microstrip array antenna having parallel feeding structure whose consist of two parts power supplying layers each of which generates its own polarization respectively.
The broad-band dual-polarized microstrip array antenna according to the present invention arranges transmission paths for two separate linear polarization on a different layer each other in order to minimize an interference effect and a proximity feeding method and an aperture coupled method are used in order to get two separate polarization.
2. Description of the Related Arts
The general microstrip array antennas have used a dielectric substrate as a power supplying substrate having a power supplying line. Therefor the thickness of the system and the manufacturing cost increased. Also, it was possible to receive only one polarization because a patch antenna has an exciting part. Although the patch antenna has two exciting parts in case of using a single power supplying substrate, there is no sufficient space for arranging an exciting transmission line for another polarization, and the bandwidth of the antenna decreases in case of having a serial feeding type transmission line structure, and the transmission line structure becomes complicated and the bandwidth of the antenna decreases in case of having a mixing transmission line structure of the serial feeding type and the parallel feeding type.
FIG. 1 illustrates a traditional microstrip array antenna. In the FIG. 1, the reference number (1) indicates a power input part. After inputted, the power is divided into two transmission lines in the direction of up and down of the power input part (1) and is divided again into two parts in a left and a right direction of a power distributor (2). And the number (3) is an exciting part for transmitting the inputted power to a patch antenna (4). As described in the above, the traditional microstrip array antenna is capable of receiving only one polarization because having only one exciting part (3).